Sunday, August 31, 2008

Extracting facebook friends from public profiles

Today I just discovered a small little disclosure issue with facebook and google. Actually, the discovery was due to my girlfriend.

When you enter a public facebook profile for a person, it will display five friends of that person. Since everybody who is friends with this person also have a public profile, which also lists five friends, there is a reasonable chance that the person turns up in their profile.

Google indexes these pages, so it is possible to search these public profiles. By searching for the a particular name on facebook using google, it is possible to find a lot more friends of the person. For instance, the query

http://www.google.com/search?q=%22Christian+Theil+Have%22+site:facebook.com&hl=en&safe=off&filter=0

will list a few of my facebook friends.

I imagine that it is possible to extract quite a big portion of the facebook social network using this method.

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